The present invention relates to devices for suspending structural elements from an overhead surface, and more particularly pertains to a device for suspending a rail from an overhead surface, such as the ceiling of a mine tunnel.
After one or a number of mine tunnels, which may vary widely in length, have been constructed into and through a seam or strata of ore-bearing rock or earth, various machines and devices must be employed to dig and remove the ore from the mine tunnel. Because of the chemical composition, location (surface versus subsurface), and difficulty of extraction for each particular ore, specialized devices and machinery have been developed for mining the numerous ores essential for contemporary industrial manufacturing processes and techniques. In addition to the above factors, a mining operation must also consider: 1) whether the ore to be mined is located in a self-supporting geologic structure or whether the geologic structure requires man-made mechanical supporting; 2) whether the ore to be mined is of a powdering or non-powdering variety; 3) whether the mining of the ore creates a gassy or non-gassy condition within the mine tunnel; and 4) the height and width of the mine tunnel. Mine tunnel ceilings can be as low as four feet while the width of coal mine tunnels varies from fourteen to twenty feet (sixteen feet being the average width), and potash mine tunnels have self-supporting ceilings and widths of between thirty-five to forty feet.
Thus, the specialized long wall technology for mining anthracite coal, for example, will differ from the specialized technology employed in mining potash, which is a salt-like substance and a self-supporting geologic structure for mining purposes. Potash is a non-powdering mineral and a potash mine is non-gassy. Moreover, because potash is a self-supporting geologic structure, no ceiling structure is required. The contrast between the conditions involved in potash mining as opposed to coal mining is given to illustrate how the mining of each kind of ore is a unique endeavor necessitating special considerations and specialized technology.
In the mining of an ore which is a self-supporting geologic structure (i.e., potash), a continuous conveyor system is frequently utilized to continuously transport ore out of the mine. A continuous conveyor system typically includes a continuous conveyor belt, some type of truss assembly for supporting the continuous conveyor belt, a monorail which defines the path of travel for the conveyor belt and truss assembly and from which both the belt and the truss assembly are suspended, and a means to suspend the monorail--and, as a consequence, also the conveyor belt and the truss assembly--from the overhead mine ceiling. The monorail itself comes in standard eight-foot segments which can be added or removed as needed in order to suspend the conveyor system therefrom.
U.S. Pat. No. 4,896,764 discloses one example of an apparatus for carrying, advancing, and retracting a conveyor in a mine to remove ore from the mine, and also teaches the use of ceiling bolts to suspend the monorail from the mine tunnel ceiling. This manner of suspending the monorail does not allow for any kind of adjustment in the suspended distance of the monorail from the ceiling once the bolts are inserted into the mine ceiling, nor does it allow vertical adjustability of the ceiling bolts which would compensate for the undulation of the mine ceiling so that the generally level suspension of the monorail can be attained. The monorail must be suspended in a generally parallel, elongate line, and this type of suspension must be achieved despite the fact that few, if any, mine ceilings will be perfectly even. Thus, a system or device which allows for selective adjustability thereof to compensate for mine ceiling undulation yet maintains suspension of the monorail in a generally parallel, elongate line from the ceiling is an advantageous enhancement for any conveyor system.